We present exact calculations of the partition function in the presence of defect networks
using the lattice regularisation of two-dimensional Yang-Mills
theory in Section REF . This shows in particular
that the defects corresponding to the symmetry induced by \(\varphi \)  agree with the
defects constructed
in [1]}.
The weak-coupling limit of two-dimensional Yang-Mills theory can be used to compute
the symplectic volume of
the moduli space of flat connections on \(\Sigma \)  [2]}. Similarly, we argue in
Section REF  that the weak-coupling limit of two-dimensional Yang-Mills theory
in the presence of defects computes the symplectic volume of the moduli space of
flat twisted bundles on \(\Sigma \) , introduced for example in [3]}.
